Oct 2018 DOI 10.14302/issn.2328-0182.japst-18-2344
Muschietti LilianaCorresponding author
Universidad de Buenos Aires, Cátedra de Farmacognosia, Facultad de Farmacia y Bioquímica (UBA), IQUIMEFA (UBA-CONICET), Buenos Aires, Argentina
In recent years, the consumption of dietary supplements (DS) has increased worldwide. In Argentina, approximately 14 million DS units were sold between 2015 and 2017. The adulteration of DS with active pharmaceutical ingredients or their analogues has been reported. This represents an alarming emerging risk to public health. The aim of this work was to detect the possible adulteration of a DS marketed in Argentina for the treatment of erectile dysfunction. Initially, thin layer chromatography analysis of the DS capsules content suggested the presence of a major compound. For the isolation and purification of this compound, an easy method consisted of a liquid-liquid extraction (water/CH2Cl2) followed by re-crystallisation from ethanol, is reported. Spectroscopic techniques such as mono- and bidimensional nuclear magnetic resonance, Fourier transform infrared spectroscopy and mass spectrometry allowed its identification as tadalafil. A rapid and reliable method was developed for the quantification of tadalafil in this DS by high performance liquid chromatography-mass spectrometry (HPLC-MS/MS). The mean content of tadalafil per capsule was 21.2 mg which represents a slightly higher value than that found in approved products in Argentina (5 or 20 mg per tablet). In addition, an undeclared alga was identified in the DS by microscopic techniques.
Mar 2013 DOI 10.14302/issn.2328-0182.japst-12-173
N. Patel BhavinCorresponding author
Bio-Analytical Laboratory, Cliantha Research Ltd., Bodakdev, Ahmedabad-380054, Gujarat, India.
A reliable, selective and sensitive liquid chromatography-tandem mass spectrometry (LC-ESI-MS/MS) assay has been proposed for the determination of febuxostat in human plasma using indomethacin as the internal standard (IS). The analyte and IS were extracted from 200 µL of human plasma via liquid-liquid extraction using methyl tert-butyl ether. Chromatography was performed on Hypurity C18 (100 mm × 4.6 mm, 5 µm) column under isocratic conditions. Detection of analyte and IS was done by tandem mass spectrometry, operating in negative ionization and multiple reaction monitoring mode. The deprotonated precursor to product ion transitions monitored for febuxostat and indomethacin were m/z 315.1 →271.0 and 356.1→312.0 respectively. The limit of detection (LOD) and limit of quantitation (LOQ) of the method were 0.0025 µg/mL and 0.05 µg/mL respectively. The linear dynamic range validated for febuxostat was 0.05-6.00 µg/mL. The intra-batch and inter-batch precision (% CV) was ≤ 7.1 % while the mean extraction recovery was > 87 % for febuxostat across quality control levels. The method was successfully applied to a bioequivalence study of 80 mg febuxostat tablet formulation in 14 healthy Indian male subjects under fasting and fed condition. The reproducibility in the measurement of study data was demonstrated by reanalysis of 110 incurred samples.